The present invention relates generally to pyrovalves, and specifically to a contamination free pyrovalve.
An example of a known pyrovalve is shown in FIG. 1 in cross-section. A shear section 10 provides for opening a valve 13. As known to those of ordinary skill in the art, a section of pipe 16 is machined with a slug 22 disposed there between such that the valve 13 is normally closed. As shown in FIG. 1, the shear section 10 is typically a one-piece machined assembly. The slug 22 is positioned such that the downward force of a ram 25 causes reduced width sections 28 to fracture such that the slug 22 is capable of translatory motion in the direction of the ram 25. The ram 25 is propelled downward by means of an explosive as known to those of ordinary skill in the art. The force of the ram 25 propels the slug 22 downward onto a projection 31 such that the slug 22 clears the two sections of pipe 16, 19 and the valve 13 is opened. When these types of valves are activated, fine metal particles that are produced by the shearing of the metal may enter the pipes.
Accordingly, what is needed is a contamination-free pyrovalve that does not require the shearing of metal and therefore reduces the likelihood of producing fine metal particles.
The present invention meets the above-described need by providing a contamination free pyrovalve. The present invention provides a valve having a slug that is press fit into position to establish a normally closed valve. By having the slug pressed into position, there is less of a chance for shearing of metal when the ram dislodges the slug to open the valve.
The present invention comprises a contamination-free pyrovalve having first tubing section and a second tubing section. The first and second tubing sections are disposed in spaced-apart relation such that a conveying path between the first and second tubing section is established. An opening is disposed between the first and second tubing sections. A valve body is fixedly attached to the first and second tubing sections. The valve body has a bore. A ram is disposed inside the bore of the valve body.
A slug is disposed in the opening between the first tubing section and the second tubing section. The slug is held in position by a frictional fit.
A combustion chamber is disposed in operative relation to the ram such that when an explosive material is ignited the pressure inside the chamber causes the ram to move through the bore to strike the slug and to displace it from the opening between the first and second tubing sections such that the valve is opened.
The valve of the present invention may also include a deceleration post that engages with a bore disposed in the slug.